Chaotic Signal Induced Delay Decay in Hodgkin-Huxley Neuron

It is a well-known fact that there are chaotic behaviors of neurons in the brain. These chaotic behaviors may affect the membrane potential dynamics of neurons. In the current study, we present a new phenomenon, called as Chaos Delayed Decay (CDD), which emerges when the first spike latency of a periodically forced deterministic Hodgkin-Huxley neuron exhibits a prominent delay depending on the chaotic current intensity. First, we indicate that the firing rate of the Hodgkin-Huxley neuron exhibits resonance-like dependence on the intensity of chaotic current. Then, we demonstrate that the first spike latency and jitter exhibits a resoance-like dependence on the chaotic current intensity for frequencies separating subthreshold and suprathreshold frequency regions. Besides, the obtained results reveal that chaotic activity may have unfavorable effects on the response of Hodgkin-Huxley neuron in the region of supra-threshold frequencies where the lowest mean latency and jitter occur. In this region increasing chaotic activity has augmented the latency and jitter in contrast to sub-threshold frequency region in which the mean latency and jitter of Hodgkin-Huxley neuron reasonably decrease versus increasing chaotic current intensity. It is also shown that, in this regime, the mean latency and jitter are insensitive to changes in frequency for high chaotic current intensities. Lastly, we have analyzed the effects of the phase of the forcing signal on the latency and jitter of the neuron. For a forcing signal in the lower sub-threshold region and an optimal one in the supra-threshold region, it is observed that there is an optimal initial phase of the forcing signal for the best encoding of information by the neuron, whereas the mean latency and jitter are insensitive to changes in the initial phase of the forcing signal in the upper sub-threshold region with high frequencies.